Re: [PATCHv1 dont apply] RFC: kvm eoi PV using shared memory

Michael S. Tsirkin
2012-04-16T18:11:19Z

On Mon, Apr 16, 2012 at 06:10:11PM +0300, Gleb Natapov wrote:
> > > lapic changes should be minimal.
> >
> > Exactly my motivation.
> >
> My patch removes 13 lines more :)

Haven't checked whether your patch is correct yet
but I see it's checking the eoi register on each exit.

I think it's clear this would make code a bit shorter
(not necessarily clearer as we are relying on ) but
as I said even though the extra overhead is likely
negligeable I have a feeling it's a wrong approach since
this won't scale as we add more features.

Let's see what do others think.

> > I also find the logic easier to follow as is -
> > it is contained in lapic.c without relying
> > on being called from x86.c as just the right moment.
> >
> See the patch. It change nothing outside of lapic.c.

True but you rely on x86.c to call kvm_sync_lapic_from_vapic
at the right time before injecting interrupts.
I haven't checked whether that is always the case but
to me, this makes the code less clear and more fragile.

Again, it appears to be a matter of taste.

--
MST